Cyanine dyestuffs and dyestuff intermediates



Patented Mar. 19, 1946 John David Kendall, Ilford, England, ass'ignor to Ilford Limited, Ilford, England, a company of Great Britain No Drawing. Application February 16, 1942-, Se iilgi No. 431,165. In Great Britain April 7,

9 Claims.

This invention relates to the manufacture of dyestuffs and dyestufi intermediates and particularly to the manufacture of dyestuffs suitable for sensitising silver halide photographic emulsions.

In copending application No. 431,164 filed on even date herewith, corresponding to British application No. 4,601/41 there is described the production of compounds of the general formula:

R S (I) where R is an alkyl group or an aralkyl group, R1 is a hydrogenatom or an alkyl', aryl or aralkyl roup, D1 is the residue of a heterocyclic nitrogen compound, and n is nought or 1.

Furthermore, in co-pending application No. 431,167 filed on even date herewith, corresponding to British application No. 4,604/41 there is described the production of compounds of the general formula:

In some cases it is desirable to carry out the reaction in the presence of analcohol BzOH in order to convert the HX formed into Box.

In the second case the course of the reaction is an addition of the groups X and R: as follows? It will be observed that if the alkyl or aralkyl group of the quaternis'ing salt is difierent from the group R2 then the two groups R2 in the final product will be difierent. It is to beunderstood that the present invention includes the intermediates oi the formula stated Whether the groups R2 are the same or diiferent.

According to a further feature of this inven tion d-yestufis are obtained by condensing, in the presence of a base and a solvent, a compound of the general Formula III with one of the following types of compounds:

to) A five-inembered ring compound contain ing the system:

Pa N/LCODCHQ where R: is a hydrogen atom or a hydrocarbon group and D2 is the residue of a heterocyclic nitrogen keto methylene nucleus.

(15) A quaternary salt of a heterocyclic nitrogen compound having a reactive methyl group,

mono-substituted methyl group or external methylene group or N-reactive amino or imino group in the c: or 7 position to a heterocyclic nitrogen atom, e. g. a compound of the general formula:

where'A is the residue of a thiazole, oxa-zole or selenaz'ole nucleus (includin the benz and benzbenZ compounds of this type) or of a thiazoline, oxazoline or selenaz'oline nucleus, R6, R7 and Rs are hydrogen atoms or hydrocarbon groups, m an integer Erfitr t'hflfi 1 (X bllig' an oxygen, sulphur or selenium atom) (d) Compounds of the general formula:

V r rz co c o T R: CH:

where D2 and R3 have the meanings assigned to them above, and R9 is a hydrogen atom or ahyh drocarbon group.

The foregoing compounds a to d are characterised by the fact that they all contain a reactive CH2 group or a reactive NI-I group (a reactive T methyl group, which may be written as CH2--I-I,

j includes a reactive methylene group), A

Where in the foregoing formula reference is made to the fact that a group may be a hydrocarbon group, it is intended to imply that the group in question may be an alkyl, aryl, aralkyl group or an unsaturated hydrocarbon group; examples are methyl, ethyl, propyl and butyl groups and higher fattty alkyl groups, benzyl and naphthyl-methyl groups, phenyl and naphthyl groups, allyl and cinnamyl and like groups. Where the hydrocarbon group contains an and residue, such residue may itself be substituted, e. g. with alkyl or aralkyl groups, oxyalkyl groups, alkyloxy groups, amino groups, hydroxy groupsand halogen atoms. 7

According to a further feature .of the invention, when the five-membered ring compound of type a above, which is condensed with the quaternary salt of the compound of Formula III-corresponds to th general formula:

(R3 being a hydrogen atom or a hydrocarbon group, and X being an oxygen, atom or a sulphur atom) the resulting product contains a thione' grouping and so may be treated with an alkyl or aralkyl salt and condensedwith any of the compounds a to d enumerated above, i. e. the process of the invention may be repeated to add a further group to the product. p

When this second condensation is with a fivemembered ring compound of type a above which also corresponds to the general formula:

(R3 being a hydrogen atom or a hydrocarbon group and X being anoxygen' atom or "a sulphur atom) the product will once more contain a thione grouping, and by proceeding in this 'vfay'the condensation may be repeatedas often as desired;

the final product obtained by any s'uchlseries of condensations may be further condensed accord-, ing to the invention with any of the other types of compound 72 to d above to give a dyestuff comprising two nuclear groups,rfor example, heterocyclic nitrogen nuclei, linked by a chain of any desired number of keto-thiazoline or keto-oxazoline rings.

Examples ofthe compounds of type; a, which may be condensed with thecompounds vof Formula- III according to our inventioniare rhodanic acid and N-hydrocarbon' substituted rhodanic acids. 2-thio-4-keto tetrahydro-oxazole and NZ-hydrpcarbon substituted compounds ,qf; thi type, and the compounds enumerated in the specification of;

British Patent No. 426,718 filed October 3, 1933,

namely oxindoles, pyrazole-fi-ones, hydantoin. thio-hydantoin, \p-hydantoin, ,b-thio-hydantoin.

Qor npounds oftype hwhich "may :be employed mayzbe any of those which have been used or proposed for use in the many processes for the pro- 'duction of cyanine and similar dyestuifs, for ex- .ample, thiazoles, oxazoles, selenazoles and their polycyclic homologues such as those of the benzene,"n'aphthalene, acenaphthene and anthracene series; pyridine and its polycyclic homologues such as quinoline-and a and 8 naphthaquinolines,

lepidine's; indolenines; diazines, such as pyrimidines and quinazolines; diazoles (e. g. thio-fifi'-' -many processes for the production of cyanine and similar dyestufis, forexample, those listed in the preceding paragraph.

The compounds of general Formula III may be obtained, as indicated above, by the treatment of *a compound of general Formula Iwith an alkyl or aralkylsalt. Alternatively they may beobtained by the treatment oi a compound of the general Formula II with an alkyl or aralkyl salt.

The formation of the dyestuffs is readily ef- :fected by heating the reagents together, preferably in the presence of a solvent, and a base, e. g. pyridine, piperidine, diethylamine, triethylamine and triethanolamine, or an inorganic base such as a solution of sodium or sodium acetate in ethyl .1: alcohol. In those processes where the compound of, general Formula III is condensed with an alkyl or aralkyl quaternary'salt of a heterocyclic nitrogen base, the conversion of the heterocyclic nitrogen'base to the quaternary salt by treatment with an 'alkyl oriar'alkyl' salt may be effected simultaneously with the formation of the dyestufi by heating a compound or Formula III, the hetero cyclic' nitrogen base and the alkyl or aralkyl salt. Thus} for example; the dyestufis may be obtained byfusingltogetherl a "compound of the described in co-pending application No. 431,167fi1ed on even date herewith, (corresponding to British application 4,604/41) a heterocyclic nitrogen compound containing 'an'external reactive methyl group in the on Or 7 position to the heterocyclic nitrogen atom, and an alkyl sulphate or an alkylp-toluene sulphonate. 7

Where the dyestuff is obtained in the form of a sulphate or an alkyl-p-toluene sulphonate, it

may be convertedtc a salt of another acid by treatment with-ajsolution 01f" anlalkali salt of such "other acidgei g", potassium chloride, potassium, br'ofmide or pbtassiumiodide. I l

Theifollowing example's'illustrate the inven- "tion:

EXAMPLE I Preparation of w-l-bis-methylthiovinyl-benzthz'azole ethzodide 5 gins. of (N-ethyl-dihydrobenzthiazolylidene- 1)-,dithioacetic acid, '5, ccsxotmethyl iodide and 0.7 cc. of methyl alcohol were mixed together and boiled with 200 cos. of dry benzene for one hour.

The hot solution was then filtered and cos. of methyl iodide and 0.5 cc. of methyl alcohol were added to the filtrate. The filtrate was then boiled for one hour and the desired product separated as a brown crystalline solid. The solution was then cooled and filtered, and after purification by boiling out with methyl alcohol, the product was obtained as a pale yellow solid. Melting at 199 C.

EXAMPLE II Pvieparation of w-l-bis-methylthio-vinyl hen...- thiazole methiodz'de 2.4 gms. of (N-methyl-dihydrobenzthiazo1ylidene-l-dithioacetic acid, 6 cc. of methyl iodide and 1 cc. of methyl alcohol were mixed together and heated in a sealed tube at 100 C. for seventeen hours. The mixture was cooled, and the separated solid material removed by filtration. The solid material was washed with methyl alcohol and yielded the product as a dark red solid, melting at 191 C. with decomposition.

EXAMPLE Ill Preparation of the dyestufi of the probable for- SCHa (E2115 EXAMPLE IV Preparation of the dyest'uii of. the probable formula:

The process was carried out as in Example III using 0.7 gm. of lepidine methiodide, 0.95 gm. of w-l-bis-methylthiovinyl-benzthiazole ethiodide, 25 ccs. of absolute alcohol and 0.5 cc. of triethylamine. The product was obtained as green crystals melting at 189 C.

Exmrns V Preparation of the dyestuif of the probable formula? SCHa The process was carriedout-as in- Example III using 1.2 gms. of .1-methyl -4-chlor-benzthiazole ethlodide, 0.7 gm. of w-l-bis-methylthio-vinylbenzthiazole ethiodide, 20 ccs. of absolute alcohol and 0.4 cc. of triethylamine. The product after recrystallisation from methyl alcohol solution was obtained as dark green crystals melting at 164 C. When incorporated in a gelatino silver iodo-bromi'de emulsion, this dyestuff extends the sensitivity of the emulsion to about 7000 A. with a maximum at about 6750 A.

EXAMlLE. VI

Preparation of the dyestuff of the probable formula:

The process was. carried out as in Example III using 0.45 gm. of p-toluquinaldine methiodide, 0.75 gm. of w-1-bis-methylthio-vinyl,-benzthiazole ethiodide, 20 ccs. of absolute alcohol and 0.3 cc. of triethylamine. The product after recrystallisation. from methyl. alcohol solution was obtained as blue crystals, melting at 210C.

When incorporated in a gelatino silver iodobromide emulsion, this dyestufi extends the sensitivity of the emulsion to about 7000 A. with a maximum at about 6800 A.

ExAmmVII Preparation of the dyestuff of the probable formula:

The process was carried out as in Example III using 1.4 gms. of quinaldine methiodide, 1 gm. of w-1-bis-methylthio-vinyl-benzthiazole ethiodide, 25 cos. of absolute alcohol and 0.6 ccof. triethylamine. The product was obtained as bronzegreen crystals.

Exnmns VIII The preparation of the dyestuff of the probable formula:

C2Hs

The process was carried out as in Example III using 0.6 gm. of l-methyl-benzthiazole ethiodide. 0.41 gm. of w-1-bi's-methylthlo-vinyl-benzthiazole ethiodide, 15 cos. of ethyl alcohol and 0.22 cc. of triethylamine. The product after recrystallisation from methyl alcohol solution was obtained as a green. dyev melting at 204 C.

Whenv incorporated ina. gelatino silver i-odo bromideemulsion this dyestufi extends the. sensitivity of the; emulsion to about 6600 A. with a EXAMPLE XII 7 maximum a about? 6200 Preparation of the ,dyestufi of probable for- 1T 1 molar 3 'ExmmIX 1i Preparation of the dyestufi of the probable for 1 55 mulaz v o v C CH=O HA I? S C=S CH3 o N sou;

w 01H; I N 5033 0.4 gm. of '2-w-dimethyl-dimercapto vinyl benz- JJH; thiazole ethiodide, 0.32 gm. of N-methyl oxindole and 15 cos. of absolute alcohol were mixed toe p e s carried out as n Example III gether and boiled. 0.2 gm. of triethylamine was using 0.8 gm;of N-ethyl rhodanio acid, l gm. of added and boiling continued for one hour. A 1 S -methylthio-vmyhbenzthlazolemethifldide, little pyridine was then added to the pink solution CCS. 0f absolute alcohol and as cc. of triethylwas ooled until the desired product epamine. The product precipitated from S lu arated as a light pink solid. After recrystallising immediately after the addition of the triethylfrom ligroin the product was obtained in t amine and no pyridine wa therefore addedform of green needles with blue reflex and melt- After boiling and filtering the solution, the proding t 90 C not was obtained as a. purple solid melting at 25 EXAMPLE X111 239 C. I

' EXAMPLE X Preparation of the dyestufi of probable for- V mula: Preparation of the dyestufi of the probable for-' S mula: r s

I CH S CH=C g CCH=C s 1 son, 02H

o-oH=o 1 CH: I son; V N 1.1 gms. of lz-dimethyl benzthiazole, 0.8 gm. of 1 (N .-methyl dihydrobenzthiazolylidene-l) dithio 40 acetic acid methyl ester and 2.7 ears. of ethyl-p- 1.07 gms. of A-oyclohexenyl-benzthiazole, 0.6 gm. toluene sulphonate were mixed together and of e y yd be z a lyl fused at Mil-150 c. for 3 hours. 20 cos. of pyrithio-acetic cid ethyl e r d 6 gm 0f dine were then added and the mixture boiled y -pphonate were mixed tofor half an hour and then poured into an aqueeether and fused for 2% hours at 160 C. 15 cos. ous solution of potassium iodide. The product f pyrid e Were t e dded and t e mixtu separated and was recrystallised from methyl boiled for half an hour and then poured into an alcohol. The dye was thus bbtained as red flaky aqueous solution of potassium iodide. Th'e prodcrystals melting at 224 C. uct separated as green crystals having, after 'recrystallisation from methyl alcohol solution, a EXAMPLE XIV melting point of 212 C. V

r Preparation of the dyestufi of probable for- EXAMPLE XI mula: mm

Preparation of the 'dyestufi of the probable for- S mulaz I T I J /CH=C o-s V V\N CH N oul s\ //i o=ono\ o0 tel/15 \I som (52H, 0:011-0 0 f N/ r f a i 7 1 c 4 The process was carried out as in Example N SCH: XIII using 1.1 gins. of 1:4-dimethyl benzthiazole, (32m 0.8 gm. of (N-methyl-lz2-dihydro equinolylidene- 2) -dithio acetic acid methyl ester and 2.7 gm's. 0.5 gm. of the dyestufi produced according to of ethyl-p-toluen sulp t T pr d t Example III, 0.3 gm. of l-methyl-benzthlazoleand which separated from the aqueous potassium 1.2 gms. of ethyl-p-toluene sulphonate were iodide solution was triturated with benzene prior mixed together and fused for 1 /2 hours at 160 to recrystallising from methyl alcohol. The dye c. 15 cos. of pyridine were added and the mixture Was thus Obtained as green crystals melting at refluxed for forty minutes and then poured. into an aqueous solution 0f potassium iodide, o When incorporated in a gelatino silver iodocooling, the product 7 separated as dark green bromide emulsion, this dyestufi extends the sencrystals having, arterreorystamsation from w sitivity of the emulsion to about 6900 A. with a methyl alcohol a melting point of 263 C. maximum at about 6400 A.

EXAMPLE XV Preparation of the .dyestuff of probable formula:

cn-o SCHs CH3 I mide emulsion, this dyestuff extends the sensitivity of the emulsion to about 7200 A. with a maximum of about 6800 A.

EXAMPLE XVI Preparation of the dyestuff of probable formula:

1.1 ms. of 1:4-dimethyl benzthiazole, 0.85 gm. of (N-ethyl-dihydrobenzthiazolylidene-1)-dithio acetic acid methyl ester and 2.7 gms. of ethyl-ptoluene sulphonate were mixed together and fused 0123 hours at 140 C. cos. of pyridine were then added and the mixture boiled for half an hour and then poured-into an aqueous solution of potassium iodide. Benzene was added with stirring and the mixture allowed to stand for 16 hours. The product which separated was recrystallised from methyl alcohol to give a green dye melting at 182 C. When incorporated in a gelatino silver iodoebromide emulsion, this dyestufi extends the sensitivity of the emulsion to about 6900 A. with a maximum at about 640.0 A.

EXAMPLE Preparation of the dyestufif of probable formula:

1.4 gms. of :2-methyl -naphthathiazole, 0.85 gm.

was washed with boiling benzene and then extracted with hot methyl alcohol. On cooling the methyl alcoholic liquor, the dye separated as green crystals melting at 134 C. When incorporated in a gelatino silver iodo bromide emulsion, this dyestufi extends the sensitivity of the emulsion to about 7000 A. with a maximum at about 6600 A.

EXAMPLE XVIII Preparation of the dyestufi of probable formula:

The process was carried out as in Example JUII using 0.54 gm. cyclohexenyl benzthiazole, 0.8 gm. of (2-ethyl-4:5-dimethoxydihydrobenzthiazolylidene-1)-dithio acetic acid methyl ester and 2.7 gms. of ethyl-p-toluene sulphonate.

EXAMPLE XIX Preparation of the dyestui'f of probable formula:

/ son; .1 CH- /N\ C2115 EXAMPLE XX Preparation of the dyestufi of probable formula: I

\ s 0H=o /CCH=C\ son I C N can C455 I The process was carried out as in Example XIII using 0.92 gm. of 1 methyl-4-ch1oro-benzthiazole, 0.7 gm. of (.2-ethyl-4-methyl-dihydrobenzthiazolylidene-i) -di-thio acetic acid methyl ester and 2.0 gms. of ethyl-p-toluene sulphonate. The prodnot was obtained as a green dye melting at 182 C. When incorporated in a gelatino silver iodobromide emulsion, this dyestuff extends the sensitivity of the emulsion to about 7200 A. with a maximum at about 6700 A.

M EX M E l Preparation of the dyestuff of probable formula:

0.6 gm. of l-methyl-benzoxazole, 0.6 gm. of (N- ethyldihydrobenzthiazolylidene-1) -dithio acetic acid methyl ester and 2.0 gms, of ethyl-p-toluene sulphonate were mixed together and fused for 3 hours at 140 C. 15 cos. of pyridine were then added and the mixture boiled for half an hour and then poured into an aqueous solution of potassium perchlorate. The product separated, and was recrystallised from methyl alcohol to give a brownish coloured dye melting at 230 C. When incorporated in a gelatino silver iodo bromide emulsion this dyestufi extends the sensitivity of the emulsion to about 6300 A. with a maximum at about 5500 A.

EXAMPLE of the dyestuff of probable for- SCH:

Preparation mula:

EXAMPLE XXIII Preparation of the dyestufif of probable formula:

0.94 gms. of 2 w dimethyl dimercapto vinylbenzthiazole methiodide, 1.07 gms. of 1-phenyl-3- methyl-4-isopropylidene-5-pyrazolone and 20 cos. ofethyl alcohol were boiled together and 1 cc. of triethylamine was added. The mixture was then boiled for half an hour and then cooled,'whereupon a black tar separated. This tar was dissolved in hot ethyl alcohol and then cooled whereupon the product separated as black crystals. After boiling out with methyl alcohol the dye was obtained as a shining black solid melting at 219 C.

As stated above, and as indicated in the foregoing examples, the dyestuffs of this invention are 7 general formula:

valuable sensitisers for silver halide photographic emulsions. They may be incorporated in silver halide emulsions of all types, e. g. silver chloride, silver bromide, silver chlorobromide and silver iodobromide emulsions. The quantity oi! sensitising dye employed will, of course, vary with the particular dye and with the purpose for which the emulsion is intended. In general, for a typical emulsion containing the equivalent of 2% silver calculated as metal, the proportion may range between 250 and 1250 cos. of a 1 in 2,000 solution per litre of emulsion.

What I claim is: I

1. Process for the production of dyestuffs which comprises condensing a compound of the general formula:

D1 SR: NZcH-oi1 ,T=c-om=c R/ \X SR: where R and R2 are selected from the class consisting of alkyl and aralkyl groups, R1 is selected from the group consisting of the hydrogen atom and alkyl, aryl and aralkyl groups, D1 is the residue of a heterocyclic nitrogen compound of the type used in cyanine dyes, X is an acid residue and n is selected from the group consisting of nought and 1, with a heterocyclic nitrogen compound containing a reactive methylene group of the type used in cyanine dyes. r

2. Process for the production of dyestufis which comprises condensing a compound of the general formula:

where R and R2 are selected from the class consisting of alkyl and aralkyl groups, R1 is selected from the group consisting of the hydrogen atom and alkyl, aryl and aralkyl groups, D1 is the residue of a heterocyclic nitrogen compound of the type used in cyanine dyes, X i an acid residue, and n is selected from the group consisting of nought and 1, with a five membered ring compound of the general formula:

D: N-co-oH, t. where Dr is the residue of a heterocyclic nitrogen keto-methylene compound and R3 is selected from the group consisting of the hydrogen atom and hydrocarbon groups.

3. Process for the production of dyestuffs which comprises condensing a compound of the where R and R2 are selected from the class consisting of alkyl and aralkyl groups, R1 is selected from the group consisting of the hydrogen atom and alkyl, aryl and aralkyl groups, D1 is the residue of heterocyclic nitrogen compound of 4. Process according to claim 3 wherein the hydrocarbon substituent grouping which includes a reactive methylene groups is of the formula:

which comprises condensing a compound of the general formula:

where R and R2 are selected from the class consisting of alkyl and aralkyl groups, R1 is selected from the group consisting of the hydrogen atom and alkyl, aryl and aralkyl groups, D1 is the residue of a heterocyclic nitrogen compound of the type used in cyanine dyes, X is an acid residue,

and n is selected from the group consisting of nought and 1, with a five-membered ring compound of the general formula:

1 R9 n oo o=o Rs CH3 where D2 is the residue of a heterocyclic nitrogen keto-methylene compound and R3 and R9 are selected from the group consisting of hydrogen atoms and hydrocarbon groups.

6. Process for the production of dyestufis which comprises condensing a compound of the general formula:

where R and R2 are selected from the class consisting of alkyl and aralkyl groups, R1 is selected from the group consisting of the hydrogen atom and alkyl, aryl and aralkyl groups, D1 is the residue of a heterocyclic nitrogen compound of the type used in cyanine dyes and n is selected from the group consisting of nought and 1, with a heterocyclic nitrogen compound of the type ,used in cyanine dyes containing in one of the a and 'y positions to the heterocyclic nitrogen atom a reactive methylene group, in the presence of sufiicient of a salt of the formula RzX, where X is an acid radical and R2 is a radical taken from the group consisting of alkyl and aralkyl radicals, to convert both of said reactants to quaternary nitrogen salts.

'7. Process according to claim 6 wherein the salt employed is selected from the group consisting of alkyl and aralkyl-p-toluene sulphonates.

8. A dyestuff of the formula:

9. A dyestufi of the formula:

CnHfi JOHN DAVID KENDALL. 

